1. Technical Field
The present invention relates to a communication system for performing communication via handshaking, and to a selection of a communication scheme between communication devices.
2. Background Art
In data communication between devices, some devices perform full-duplex communication and other devices perform half-duplex communication.
Full-duplex communication is a communication scheme that allows, in two-way communication, both devices to transmit and receive data simultaneously. Full-duplex communication offers the following advantages: it is not necessary to switch between transmission and reception; it is easy to control full-duplex communication; and data transmission and reception may be performed anytime.
On the other hand, half-duplex communication is a communication scheme that, unlike the two-way communication, does not allow both devices to transmit and receive data simultaneously, and simply allows one of the devices to transmit data to the other in an allocated time. Half-duplex communication is advantageous than full-duplex communication in terms of a large capacity data transfer. For, in half-duplex communication, it is not necessary, during data transmission, to secure a bandwidth for data reception as needed in full-duplex communication, and a wider bandwidth for data transmission becomes available than the case of full-duplex communication.
Since full-duplex communication and half-duplex communication each provide different advantages, there have been disclosed in Patent Literature 1 communication devices and a communication method, which are designed to switch between full-duplex communication and half-duplex communication. According to Patent Literature 1, (i) when one of two devices requests to transmit data, half-duplex data communication is performed, and (ii) when both two devices request to transmit data, full-duplex data communication is performed.